Effect of Sn Doping on Structural and Optical Properties of 2D α-MoO3 Nanostructures

Undoped and tin (Sn) doped molybdenum trioxide (α-MoO3) nanostructured thin films (which has lamellar (2D) structure) have been prepared using a simple and cost effective technique of spray pyrolysis on glass substrates at 450°C. Surface morphology, optical and structural properties of samples have been investigated using FESEM, UV-Vis spectroscopy and XRD analysis techniques, respectively. FESEM images showed the formation of some discrete micro-spheres on the surface, which with the increasing in the amount of dopant homogenous and dense nano-platelets was grown on top of these micro-spheres. The XRD pattern analysis shows that all samples have been grown in orthorhombic (α-MoO3) crystal structure and except for the sample doped with 50 at% Sn which had a weak peak of SnO2, no peak have been observed corresponding to the incorporation of Sn. By increasing the amount of impurity, optical transmittance of samples were increased from ~27 to 50%. Also, the band gap of samples were calculated using transmission data. An increasing of band gap from 3.34 to 3.89 eV was observed with increasing in the amount of doping.